What influence did Greek philosophy have on the formation of orthodox Christian doctrine?
Particularly, what Christian doctrines or paradigms of understanding God and reality can be traced to have been influenced by Greek thought?
There were a lot of things that Greeks taught and believed that resemble what mainstream Christianity has come to embrace. For example
The concept of a soul within us that cannot die first became a ‘Christian’ doctrine at the end of the second century AD. Hell had been taught in Greek philosophy long before the time of Jesus, with Plato (427-347 BC) as the important leader in this thinking. The teaching of an everlasting place of punishment for the wicked is the natural consequence of a belief in an immortal soul. By the year AD 187, it was understood that life, once we have it, is compulsory; there is no end to it, either now or in a world to come. We have no choice as to its continuance, even if we were to commit suicide to end it.
More detail given at Truth According to Scripture
The early church fathers though maybe influenced were very much sympathetic to many stoic philosphers ideas of morality being an abstract thing not to do with the gods. As a concept of morality being written on the heart, the early church fathers knew the motivation for the ideas of logos was because the roman and greek pantheon of gods did many immoral things so the romans had to get their heads around a deity that did good and was the source of good.
In 2018 I wrote an article titled "Ousía and hypostasis from the philosophers to the councils" which probably answers most of this question, so I will just link to it. It is also in PDF format in academia.edu.
THE IDEAS OF THE PAGAN GREEK (HELLENISTIC) PHILOSOPHER PLATO & OTHERS THAT CONTAMINATED CHRISTIAN DOCTRINES.
Plato's concepts and ideas came via as follows:-
The line of Pagan Greek Philosophers that lead to Plato (and onward), and their kind of Philosophical/Theological thought that was adopted by false teachers to formulate Christian doctrines and teaching are as follows, Pythagoras (spent many years in Egypt), Parmenides, Heraclitus ('Logos') , Socrates, Plato, Aristotle, Philo (c.25 B.C.E. - 40 C.E. Jewish), Ammonius, Origen & Clement (Alexandria) & Plotinus (Neoplatonist; Rome), Prophyry, Augustine, Thomas Aquinas (Catholic) and from the Catholic Church into all other sects of Christendom’s churches down to today.
The Good* (Plato's Phaedo)
The Logos (Gk.- "ho Logos"; The Word)
The First Cause* (Plato's Timaeus)
Demiurge (Plato's Timaeus)
Theory of Ideas or Forms or Essences (Plato's Republic)
Utopia (Plato's The Ideal State)
Immortality [of the Soul] (Plato's Phaedo)
a. Reality & Appearance.
b. Ideas & Sensible Objects.
c. Reason & Sense-perception.
d. Mind & Matter
e. Soul & Body.**
f. 1st God & 2nd god**** (God from God)
g. One & Indeterminate
h. Rest & Good
i. Motion & Evil
j. Life & Mind
k.Potency & Activity* (*Aspects of the Supreme God or Divinity)
l. Reason & Principle (See No.2, Understanding)
a. God & Ideas & Matter (Jupiter, Minerva, Juno)****^^
b. God & Sophia & Logos.****
c. Father & Power & Intellect. ****
d. Being & Life & Intellect.****
e. Mind & Body & Soul.
f. First Cause & Logos & Soul/Spirit.*****
g. God & Form & Matter (Monad + Dyad)^
h. God & Logos & Matter (Monad + Dyad)^
i. Father-God & Creator-God or Logos & World-Soul****
j. Infinite Dyad & World-Soul & Matter****
k. Father & Power & Intellect****
l. Father (God) & Intellect * World-Soul****
Orphic religious teaching: That from the earth comes the Body and from heaven comes the Soul in Plato's Phaedo*.
***’The history of Western Philosophers’ by B. Russell
****’The Philosophy in Christianity’ Ed. by Godfrey Vasey
*****'The Decline and Fall of the Roman', Chap. XXI
^’Alcinous – The handbook of Platonism’ p.94
^^’Alcinous – The handbook of Platonism’ p.93
GREEK PHILOSOPHICAL IDEAS WHICH WHERE USED BY APOSTATE CHRISTIANS OF THE 2ND-4TH CENTURIES TO FORM THE TRINITY DOGMA; THE SCRIPTURAL VIEWPOINT:-
NWT 1 Corinthians 1:20-21 "Did not God make the wisdom (Gk. Sophia) of the world foolish? For since, in the wisdom of God, the world through its wisdom did not get to know God."
NWT Colossians 2:8 “Look out: perhaps there may be someone who will carry YOU off as his prey through the philosophy (Gk. philosophias) and empty deception according to the tradition of men, according to the elementary things of the world and not according to Christ; …”
GREEK PHILOSOPHY - GOD - TRIAD CHRISTIAN THEOLOGY – GOD - UNITY
First Cause; The supreme in the 'World of Ideas' Jehovah Almighty God the first cause as or 'Forms' was said to be 'Essences'
“The Good,” the Creator of the universe and life (soul).
The "One", which Plato and others sometimes identified with God, & The "Cosmic Soul."
The Logos "ho Logos" 'The Word' 'Divine Reason' The Word of God in the Hebrew Bible or 'Principle' or 'Understanding' or 'Demiurge' or God’s own declaration via messengers the "Mind of god" as manifest in Matter.
"The Word" (ho Logos, John 1:1-2) Jesus.
“Matter” an emanation from the above.
The Holy Spirit or power of God
Greek God Deity + Logos + Power = God.
The Bible’s God Jehovah God by Holy Spirit created The Word (His Son Jesus)
Christendom's God Father + Son + H. Spirit = God.